巻号一覧
5 巻 (1958 - 1959)
- 3-4 号 p. 63-
- 2 号 p. 37-
- 1 号 p. 1-
5 巻, 3-4 号
選択された号の論文の7件中1～7を表示しています
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広瀬 秀雄1959 年 5 巻 3-4 号 p. 63-69
発行日: 1959/05/10
公開日: 2011/03/01
ジャーナル フリーThe present paper deals with the discussion concerning the accuracy of a station position as determined by the so-called “equal-limb and double-station” occultation observations. Our experiments of the short range show that the purely instrumental accuracy of position determinations will be about 20 m in distance. But, in the case of long range, 2000 km or more, the apparent observational error seams to amount to about 70 m in distancce. The difference of 50 m between these two cases might be attributed to the inaccuracy of Moon's ephemeris, the effect of second order quantities and the effect of Moon's profile. The effect due to Moon's profile was studied experimentally and we found that Moon's profile will affect the result, at least, by about 10 % of the distance between the equal-limb line and the actual observation station, if the station was situated outside the line by a short distance.
The position of Japan, based on the astronomical positions of Marcus Isl., determined by several equal-limb occultation observations, seams to be in coincidence with the previous result obtained by the present author. But the discussion of the position of Japan is outside of the scope of the present paper.抄録全体を表示PDF形式でダウンロード (926K) -
田島 稔1959 年 5 巻 3-4 号 p. 70-78
発行日: 1959/05/10
公開日: 2011/03/01
ジャーナル フリーThe geographical distribution of anomalous phase difference between the vertical and horizontal components of the geomagnetic Sq variation in Japan was studiesd . by using the result of the 1st order magnetic survey the Geographical Survey Institute and the records of the l Kakioka Magnetic Observatory.
Fig. 2 shows the distribution of the value of 8 defined as follows,
δ=(tZ.S-tII.S)-(tZ.K-tII.K),
where (tZ.S t, H.S) is the time difference between the maximum decrease of the vertical and horizontal components of the Sq at the 1st order magnetic station and (tZ.K-tH.K) is that obtained at Kakioka on the same day. As shown in Fig. 2, the values of δ are zero and minus in the south-east part of Hokkaido, east part of Tohoku, almost all of Kanto and Chubu, and the south coast of Kinki and Sikoku.
In these districts the electrical conductivity seems to be very low at a depth of severalhundred kilometers.
In order to find the world wide distribution of the phenomenon above mentioned, preliminary examination was done by using the data of mean Sq for summer and winter at observatories during the Second Polar Year.
The result of the study is shown in Fig . 5, which suggests that the distribution of the zero and minus values of (tZ-tX) denoted by Δ and X has some sort of relationship to that of the deep focus earthquakes and seems to support the hypothetical model proposed by T. RIKITAKE [4].抄録全体を表示PDF形式でダウンロード (1233K) -
友田 好文1959 年 5 巻 3-4 号 p. 79-83
発行日: 1959/05/10
公開日: 2010/09/07
ジャーナル フリーIn order to obtain the vertical gradient of gravity, two kinds of methods are now being used. One is a direct method which gives the result by the use of vertical distribution of gravity, i.e. the value of ∂g/∂z is given by the difference of gravity values at two points having different altitudes. The other method is an indirect method with gives the result by the use of horizontal distribution of gravity, i.e. the value of aglaz is given by adding anomalies in ?∂g/∂z calculated from gravity anomalies to the standard ?∂g/∂z . The values of aq/az obtained by these two methods should be identical, if the difference of altitude of the two vertical sampling points are infinitesimally small and if the informa tions on the gravity anomalies at the surface are perfect. Actually this is not the case and it is expected that some amounts of difference of ∂g/∂z occur according to the difference of the method. This difference has been studied from the point of spectrum, and has been found that the direct method does not give any new information about ∂g/∂z, as far as the instrument used for this purpose is the same as the one used in the observation of horizontal distribution, that is, the value of aglaz obtained by the difference in gravity value at a vertical distance of 5 m will also be given with about the same error by theweighted sum of the gravity values at three points at the surface which are 5 m apart from each other.抄録全体を表示PDF形式でダウンロード (583K) -
友田 好文1959 年 5 巻 3-4 号 p. 84-87
発行日: 1959/05/10
公開日: 2011/03/01
ジャーナル フリーIt is usual to interpret gravity anomalies at the surface as due to an anomalous mass distribution condensed on a surface at a certain depth. If we consider an underground mass distribution which is always positive on the surface at a certain depth, we can easily calculate equivalent gravity anomalies, but it is difficult to decide from the surface anomalies whether the underground mass distribution is always positive or not. In this paper, this criterion is investigated from the stand point of the spectrum and it is found that the necessary and sufficient condition for the underground mass distribution to be always positive on the surface at a certain depth D, is written as,
G0(ω)=GD(ω)⋅e- |ω|D,
where G0(ω) represents the spatial wave number spectrum of gravity anomalies and GD(ω) represents an arbitrary auto-correlation function derived from an arbitrary function A(u)as
For simplicity's sake, we illustrate a few example when ℑGD(ω)=0, that is, the gravity distribution is symmetrical about the origin . The examples are classified into three cases.
1) The example which gives negative mass distribution somewhere on the surface at a certain depth, because GD(ω) does not satisfy the necessary condition for auto-correlation function. Gravity distribution represented by e-1/2 (χ/σ is an example of this case (Fig. 1).
2) The example which gives positive mass distribution because GD(ω) satisfies the necessary and sufficient condition for auto-correlation function. Gravity distribution represented by b/(x2+b2) or 1/{(1+x)2+1}+1{/(1-x)2+1} is an example of this case.
3) The example which does not gives positive mass distribution because GD(ω) satisfies the necessary condition only but does not satisfy the sufficient condition for autocorrelationfunction. Gravity distribution (sin πhχπhχ)2 is an example of this case.抄録全体を表示PDF形式でダウンロード (379K) -
飯田 汲事, 青木 治三1959 年 5 巻 3-4 号 p. 88-91
発行日: 1959/05/10
公開日: 2011/03/01
ジャーナル フリーGravity anomalies and subterranean mass distribution for the Nobi Plain in the Central Honshu of Japan are investigated. The method for calculating subterranean mass distribution from the gravity values is based on the theory described in our previous paper [1]. By means of a North American gravimeter the authors measured the gravity at 539 points in the Nobi plain and its southern area. The lines of Bouguer anomalies based on the International Gravity Formula are shown in Fig. 2 with 2 mgal intervals. The calculated undulation of basement for average depth of 1 km is given in Fig. 3. The Bouguer anomaly increases westward and is negative in the most part of this district. The greatest negative anomalies are located at the east side of the Yoro mountains, suggesting a geosynclinal underground structure where thick young formations are developed. There can be seen the positive gravity anomaly in the southern area of this district, suggesting that the young formations lying in this area thin out southward in connection with the geologic tectonic structure. Two main basins and four fault-like structures can be interpreted in this district from the isoanomaly lines in Figs. 2 and 3.抄録全体を表示PDF形式でダウンロード (654K) -
尾崎 幸男1959 年 5 巻 3-4 号 p. 92-95
発行日: 1959/05/10
公開日: 2010/09/07
ジャーナル フリーThe contour lines traced by photogrammetrical method have some what different meaning compared with the contours drawn by plane table surveying on the ground. By plane table survey, it is very difficult to carry out the height measuring at every points of the terrain surface, but by photogrammetry, it is far easier to mearure the heights and plane coordinates of all points on the stereomodell, and every contour lines are drawn directly by continuous height measuring on the ground. The accuracy of contour lines is affected by the condition of the terrain, (vegetation, ground inclination, and other factors), and in addition, in the case of photogrammetry, the conditions of aerial photography (camera, lens, flight altitude, exposure time, season and date of photography, climate, base-height ratio, etc.), stereoplotting instruments, and the nature of the stereo modell. There are some rules about the accuracy of contour lines; the famous C-factor used in America; Koppe's formula (4), which was applied at first to the terrestrial survey, then to the photogrammetrical case by changing its constants. But all these seem to be not enough to explain the accuracy of photogrammetrical contour-tracing, untill more detailed nature of the stereo modell is taken into account, As one attempt, we tried to introduce the effect of the inclination of the sight line which connects the nodal point of lens and the observing point on the stereo modell, and got the formulas (9), (10), and (9b), (lOb). These results can be regarded as a modification of Koppe's formula, replacing the constants a; b, by the functions of sight line inclination β, and the ground inclination α by the inclination α' of the stereo modell, in which the effect of the modell plastic is also included.抄録全体を表示PDF形式でダウンロード (616K) -
平井 雄1959 年 5 巻 3-4 号 p. 96-97
発行日: 1959/05/10
公開日: 2010/09/07
ジャーナル フリーThis paper discusses the accuracy of contour lines on the topographic maps of Sasebo area. The error of contour lines are supposed to be the superposition of error caused by model deformation, errors of observation, and of drawing and it is assumed that those three errors possess normal distributions, each of which has the same mean value and the same variance at every point in the models. The results obtained from these assumptions are: i) The mean value of the deviation is -0.4m. ii) The variance of the mean value is ±2.4m.抄録全体を表示PDF形式でダウンロード (237K)
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